The Moore, Oklahoma tornado of May 20, 2013 is now ranked an EF-5, making it one of only 59 U.S. tornadoes to achieve that distinction since record keeping began in 1950. The National Weather Service in Norman, Oklahoma announced Tuesday that their damage survey teams found an area of EF-5 damage near Briarwood Elementary School, with winds of 200 - 210 mph indicated. There were no EF-5 tornadoes observed in 2012, and the last time the U.S. had an EF-5 was on May 24, 2011, when the Oklahoma towns of Calumet, El Reno, Piedmont, and Guthrie were hit by an EF-5 with 210+ mph winds that killed nine people. The maximum width of the 2013 Moore tornado's damage swath was a huge 1.3 miles. Detailed damage survey information in Google Earth Format provided by the Norman, OK NWS office shows that the typical width of the EF-0 and greater damage swath was about 0.6 miles, and the EF-4 damage area was about 0.1 miles across at its widest. EF-4 damage occurred along approximately 4 miles of the tornado's 17-mile long path. The damage swath from the May 20, 2013 tornado as it cut through the most densely built up portions of Moore was roughly 1.5 times as wide as the one from the May 3, 1999 EF-5 tornado. That tornado was the 4th costliest in history ($1.4 billion 2011 dollars), so it is a good bet that the 2013 Moore tornado will end up being even more expensive. This morning, the Oklahoma Insurance Department said the preliminary tornado damage estimate could top $2 billion. This would make the 2013 Moore tornado the 2nd most expensive tornado in history (as ranked by NOAA/SPC) or 3rd most expensive (as ranked by insurance broker Aon Benfield.) The nine billion-dollar tornadoes (2013 dollars) are:

Figure 2. The damage swath of the Moore, Oklahoma tornado of May 20, 2013. EF-4 damage (red colors) occurred along roughly 4 miles of the 17-mile path, and the EF-4 damage swath was up to 0.1 miles wide. The tornado's maximum width of 1.3 miles (EF-0 and greater damage) occurred over a relatively small portion of the path, before the storm reached Moore. Image credit: NWS Norman.

Figure 3. On May 20, 2013, a supercell thunderstorm in central Oklahoma spawned a destructive tornado that passed just south of Oklahoma City. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this natural-color image of the storm system at 2:40 p.m. Central Daylight Time (19:40 Universal Time), just minutes before the devastating twister began. The red line on the image depicts the tornado’s track. Image credit: NASA Earth Observatory.

There have been bigger tornadoesThe 1.3 mile maximum width of the 2013 Moore tornado's damage swath was not a record. Wikipedia documents that the EF-3 Edmonson, Texas tornado of May 31, 1968 had a damage path width between 2 and 3 miles (3.2 and 4.8 km) wide. The EF-4 Wilber - Hallam, Nebraska tornado on May 22, 2004 was of similar size, with a damage path up to 2.5 miles wide. Doppler radar measurements indicate that the May 4, 1999 Mulhall, Oklahoma EF-4 tornado--which thankfully passed mostly over farmland--would have caused damage over a path 4 miles wide at its peak size, had it encountered a built-up area. The EF-5 tornado that devastated Greensburg, Kansas on May 4, 2007 was 1.7 miles wide.

Figure 4. Damage swath of the Wilber - Hallam, Nebraska EF-4 tornado of May 22, 2004 was up to 2.5 miles wide, making it one of the largest tornadoes on record.

Figure 5. Severe weather outlook for Wednesday, May 22, calls for a "Slight Risk" of severe weather over portions of the Ohio Valley and Northeast U.S. You can follow today's severe weather from our Severe Weather page.

No tornadoes reported on Tuesday; "Slight Risk" of severe weather on WednesdayThe severe weather outbreak of May 18 - 22 peaked on Sunday and Monday. We did not record any tornadoes on Tuesday, though there were many reports of large hail and damaging winds, including three thunderstorms with wind gusts over 74 mph. Tuesday was the first day since May 14 that no tornadoes were recorded in the U.S. And after issuing four consecutive "Moderate Risk" outlooks for severe weather, NOAA's Storm Prediction Center (SPC) is going with only a "Slight Risk" for severe weather on Wednesday in the U.S., with the main severe weather action expected to affect portions of the Ohio Valley and Northeast U.S. The primary threat will be straight-line wind damage and large hail, though we can't rule out a few tornadoes. During the three-day period May 18 - May 20, 70 tornadoes (preliminary) were recorded by SPC.

Video 1. Charles Cook caught the birth of the May 20, 2013 tornado at Newcastle, OK. It moved from there to Moore where it caused catastrophic devastation.

The Norman, OK NWS office has an excellent page with detailed info on the Moore tornado.

I did a 10-minute Skype interview with democracynow.org on Tuesday morning, discussing the Moore tornado.

I greatly appreciate all the valuable links members of the WU community have posted here, and I have used many of them in my posts over the past day. Keep up the great work!

How to helpPortlight Strategies, an organization that supports disaster victims with disabilities, will be working with shelter operators and disability stakeholder organizations in Oklahoma to serve the needs of people with disabilities. Further information and how to offer additional support can be found on their website.

Donations can be made to American Red Cross disaster relief at redcross.org/weather or by texting WEATHER to 90999 to donate $10.

Donations can be made on The Salvation Army's website or by texting STORM to 80888 to donate $10. You can also call to make donations of other monetary amounts at (800) 725-2769.

Quoting Neapolitan:Oh, I see. Bastardi was referring to this weekend, when the US celebrates Memorial Day with a three-day weekend. I inadvertently referred to traditional Memorial Day, which is the 30th--the first day of the 8-14 forecast. (My great-grandfather was killed at the tail end of WWI; in deference to my great-grandmother, and to abide by her wishes that we continue tradition, our family has always honored his death [and the subsequent deaths of a few others in WWII and Vietnam] on May 30, which sometimes leads to confusion, as here.)

At any rate, there may be a few flakes at higher elevations, but that forecast is totally out of whack. ;-)

"Russia has ordered the urgent evacuation of the 16 crewmembers of a drifting Arctic research station, after the ice floe that hosts the floating laboratory began to disintegrate. Natural Resources and Ecology Minister Sergey Donskoy on Thursday set a three-day deadline to draft a plan to evacuate the North Pole-40 floating research station. %u201CThe ice is disintegrating,%u201D AFP quoted a ministry spokesperson as saying. %u201CCracks appeared in the floe.%u201D If the situation is not addressed, it may also result in the loss of equipment and contaminate the environment near Canada's economic zone."

"Russia has ordered the urgent evacuation of the 16 crewmembers of a drifting Arctic research station, after the ice floe that hosts the floating laboratory began to disintegrate. Natural Resources and Ecology Minister Sergey Donskoy on Thursday set a three-day deadline to draft a plan to evacuate the North Pole-40 floating research station. %u201CThe ice is disintegrating,%u201D AFP quoted a ministry spokesperson as saying. %u201CCracks appeared in the floe.%u201D If the situation is not addressed, it may also result in the loss of equipment and contaminate the environment near Canada's economic zone."

Quoting opal92nwf:I don't understand how there was bare slabs of foundations with the debris completely swept away (which I thought was considered EF5 damage) just immediately south of Plaza Towers Elem. school, and the only EF5 damage they site is at the Briarwood school. Does anyone have an explanation?

According to the new EF-scale, homes of typical construction that are completely destroyed with all walls removed down to the slab is estimated as 200mph winds. EF5 damage starts at 201mph. Homes must have signs of higher-than-typical construction for them to be classified as EF5. http://www.spc.noaa.gov/efscale/2.html

Similar situation for elementary schools. The Briarwood school is relatively new and they likely found evidence that it was built far above code and better than typical construction such that it's damage was caused by winds near the upper bound for the degree of damage sustained.http://www.spc.noaa.gov/efscale/15.html

Quoting Neapolitan:You misunderstand; no offense was intended. I wasn't trying to turn this into a theological debate; I was merely responding to a suggestion that the church building was spared by divine intervention by saying that if that were so, I wish the divine intervener would have steered the tornado into the church and away from the kids. (Or, better yet, not have spun up an EF-5 tornado and plowed it through a populated area in the first place.)

And the original insinuation that the tornado changed direction at a church is stemming from preliminary survey tracks. If you really dig into the data, you can see that some of the survey points do not line up perfectly with the structures discussed. Also of note, you can see the delineations of damage do not match perfectly to the satellite pictures.The track still needs clean-up, and is generalized more for the city scale, yet people are trying to analyze direction changes at the neighboorhood scale that amount to nothing more than a vertex in a polygon outline.

yes if we all wish it on the church, and we praise satan instead, that should work. ridiculous. go ahead and ban me

You misunderstand; no offense was intended. I wasn't trying to turn this into a theological debate; I was merely responding to a suggestion that the church building was spared by divine intervention by saying that if that were so, I wish the divine intervener would have steered the tornado into the church and away from the kids. (Or, better yet, not have spun up an EF-5 tornado and plowed it through a populated area in the first place.)

I don't understand how there was bare slabs of foundations with the debris completely swept away (which I thought was considered EF5 damage) just immediately south of Plaza Towers Elem. school, and the only EF5 damage they site is at the Briarwood school. Does anyone have an explanation?

I can count the number of times I've been in a hailstorm on my two hands. We get it more often in Fairbanks, but most of the time the storms aren't deep enough to produce. I haven't seen hail in Norman yet, but I'm sure I will soon enough. Next week looks like it might get bad.

Oh, don't say that :(

Believe it or not, more afraid of the hail than I am of the tornadoes . . . because of the probabilities of experiencing it.

Quoting seminolesfan:Care to post any model verifications to support this statement?

Quoting Levi32:

I am here for 10 weeks to do a research project. It's an REU program. I'm one of 10 students in it this year. So far with the Moore tornado and now the activity today they have been too busy to get me started yet. It's unbelievable being in here. It's all glass walls, so I can see into SPC and HWT from where I'm sitting in the WFO. Surreal.

Hypothetically speaking, if a major hurricane were to hit the United States in the time period you're here would you be required to visit the damage area as well?

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 10N14W CONTINUING TO 8N17W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 5N27W TO 5N41W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45/60 NM EITHER SIDE OF THE MONSOON TROF E OF 16W TO INLAND OVER GUINEA. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 75 NM ALONG THE IVORY AND GRAIN COASTS OF AFRICA...WITHIN 120 NM OF LINE FROM 8N15W TO 1N27W...AND FROM 4N-9N BETWEEN 28W-42W.

Do you get hail quite often up in Alaska? I find the lightning here unimpressive (I'm originally from SoFl) but the hail is absolutely amazing to me - well, unless its bouncing off my car.

I can count the number of times I've been in a hailstorm on my two hands. We get it more often in Fairbanks, but most of the time the storms aren't deep enough to produce. I haven't seen hail in Norman yet, but I'm sure I will soon enough. Next week looks like it might get bad.

Ok. Then that would make your last comment valid. I do agree that anything past 10 days is la la land. But it still should be monitored, because its not very often that all models agree on development and then not get, at the very least, a low that attempts to develop.

This morning was unbelievable. It brought me right out of bed. I had lightning strike 1/4 mile away on a light pole right in front of my face. I've never really seen cloud-to-ground before. Amazing. We've had copious rainfall as well. It looked like a literal shower out there before sunrise. The mesonet is reporting over 2 inches of rain in some spots, and convection is still redeveloping over OKC. This is terrible for Moore.

Yes, it is.

Do you get hail quite often up in Alaska? I find the lightning here unimpressive (I'm originally from SoFl) but the hail is absolutely amazing to me - well, unless its bouncing off my car.

I think we all have "our days" yonzabam.. :)It helps when folks pitch in and help explain.. I know I need it more often these days.. :pI'm a victim of "Evelynn Woods Speed Reading Course" myself..LoL.. :)

Quoting RitaEvac:After looking at aerials on Google map of the damage, one thing stood out the most. The tornado was moving on a NE direction and where there is the Central church of Christ along I-35 the tornado literally changed to an ESE direction going opposite of the church. There is no way the tornado should of turned like that. That is by far the most stunning event I've ever seen, and the evidence of the track change is evident.

SUMMARY...MONITORING FOR AN INCREASING DAMAGING WIND/MARGINAL SEVERE HAIL HAZARD WITH INITIAL CONVECTIVE DEVELOPMENT OCCURRING ACROSS FAR ERN PA/NRN NJ. A WW ISSUANCE MAY BECOME NECESSARY WHERE GREATER CLUSTER/LINEAR ORGANIZATION IS APPARENT.

DISCUSSION...AN INCREASE IN CONVECTIVE DEVELOPMENT HAS BEEN NOTED IN RADAR IMAGERY FROM NEAR THE ABE/TTN TO 20 NW EWR AREA AS CONVECTIVE TEMPERATURES OFF THE 12Z APG/WAL RAOBS HAVE BEEN BREACHED WITH MIDDLE TO UPPER 70S IN 15Z METARS. AMIDST A PLUME OF MIDDLE TO UPPER 60S SURFACE DEW POINTS...MLCAPE HAS ALREADY REACHED 500-1000 J/KG. MODERATELY STRONG UNIDIRECTIONAL SWLY WIND PROFILES WITHIN THE RIGHT ENTRANCE REGION OF A FAST UPPER-LEVEL JET SHOULD PROMOTE ADDITIONAL CONVECTION WHICH MAY ORGANIZE INTO CLUSTERS AND SHORT-LINE SEGMENTS PRIMARILY PRODUCING SPORADIC DAMAGING WINDS AND MARGINALLY SEVERE HAIL.

Quoting HurricaneDean07:No. Beyond 240-300 hours Is lala land. 200 hours is only 8 days from now which, considering that, even our normal forecasts go out to 7 days, so really it's believable that anything within 10 days is broadly accurate.

Quoting HurricaneDean07:No. Beyond 240-300 hours Is lala land. 200 hours is only 8 days from now which, considering that, even our normal forecasts go out to 7 days, so really it's believable that anything within 10 days is broadly accurate.

SUMMARY...MONITORING FOR AN INCREASING DAMAGING WIND/MARGINAL SEVERE HAIL HAZARD TODAY WITH INITIAL CONVECTIVE DEVELOPMENT OCCURRING WRN NY INTO NWRN PA. A WW ISSUANCE MAY BECOME NECESSARY WHEN GREATER CLUSTER/LINEAR ORGANIZATION IS APPARENT.

DISCUSSION...AN INCREASE IN CONVECTIVE DEVELOPMENT HAS BEEN NOTED IN RADAR/VISIBLE SATELLITE IMAGERY FROM NEAR ROC SWWD TO FKL. AS CONVECTIVE TEMPERATURES OFF THE 12Z BUF/PIT RAOBS HAVE BEEN BREACHED. RELATIVELY ABUNDANT LOW CLOUD COVERAGE REMAINS DOWNSTREAM OF THIS WHICH IS RETARDING SURFACE HEATING...BUT GRADUAL DESTABILIZATION AMIDST THE PRESENCE OF 10-12 G/KG MEAN MIXING RATIOS MAY YIELD POCKETS OF MLCAPE FROM 500-1000 J/KG. MODERATELY STRONG UNIDIRECTIONAL SWLY WIND PROFILES WITHIN THE RIGHT ENTRANCE REGION OF A FAST UPPER-LEVEL JET SHOULD PROMOTE ADDITIONAL CONVECTION WHICH MAY ORGANIZE INTO CLUSTERS AND SHORT-LINE SEGMENTS.

This morning was unbelievable. It brought me right out of bed. I had lightning strike 1/4 mile away on a light pole right in front of my face. I've never really seen cloud-to-ground before. Amazing. We've had copious rainfall as well. It looked like a literal shower out there before sunrise. The mesonet is reporting over 2 inches of rain in some spots, and convection is still redeveloping over OKC. This is terrible for Moore.

Welcome to the lower 48, Levi.

During heavy thunderstorms, there are sometimes two bolts every second, strong winds, and rain so heavy you cant make out the features on the house across the street!